Flavoring foods by addition of unsaturated aliphatic aldehydes or precursors thereof

ABSTRACT

A METHOD OF FLAVOURING FOODSTUFFS BY INCORPORATING THEREIN AN ALIPHATIC ALDEHYDE HAVING FROM 11-17 CARBON ATOMS AND FROM 2-4 DOUBLE BONDS WITH ATLEAST ONE DOUBLE BOND NON-CONJUGATED OR BY INCORPORATING PRECURSORS WHICH FORM THE ALDEHYDE BY OXIDATION, HYDROLYSIS OR THERMAL DECOMPOSITION.

United States Patent 3,686,003 FLAVORING FOODS BY ADDITION OF UNSATU- RATED ALIPHATIC ALDEHYDES 0R PRECUR- SORS THEREOF David Adriaan van Dorp, Vlaardingen, Netherlands, and

Philip Akroyd, Rushden, Northants, and Lothar Mindt,

Bromham, Bedford, England, assignors to Lever Brothers Company, New York, N.Y.

No Drawing. Continuation of application Ser. No. 304,301, Aug. 22, 1963. This application Apr. 15, 1970, Ser. No. 28,215

Claims priority, application Great Britain, Aug. 23, 1962, 32,360/ 62 Int. Cl. A231 1/26 11.8. CI. 99-140 R 13 Claims ABSTRACT OF THE DISCLOSURE A method of flavouring foodstuffs by incorporating therein an aliphatic aldehyde having from 11-17 carbon atoms and from 2-4 double bonds with at least one double bond non-conjugated or by incorporating precursors which form the aldehyde by oxidation, hydrolysis or thermal decomposition.

This application is a continuation of application Ser. No. 304,301 filed Aug. 22, 1963, now abandoned.

This invention relates to the treatment of foodstuffs, more particularly to the treatment of foodstuffs to impart to them an improved savoury flavour.

The invention depends on our discovery that an improved savoury flavour can be imparted to a foodstuff, or such savoury flavour as it already has can be enhanced or modified, by incorporating in the foodstuff a small proportion of an aliphatic aldehyde having from 11 to 17 carbon atoms and from 2 to 4 olefinic bonds, for example:

It has also been found that the ability to impart an improved savoury flavour extends to derivatives of the above aldehydes, such as the bisulphite addition compounds and generally to compounds capable of forming the aldehydes by oxidation, autoxidation, hydrolysis, thermal decomposition, etc. Such compounds are referred to in this specification as precursors. Examples of precursors which can form the aldehydes (RCHO) by oxidation are the corresponding alcohols (RCH OH); and examples of precursors Which can form the aldehydes by hydrolysis are the corresponding acetals such as the diethyl acetals hemiacetals, and the esters (such as the acetates and propionates) of the hypothetical diols [RCH(OH corresponding to the aldehydes.

Precursors capable of forming the aldehydes by autoxidation are compounds containing the grouping Where n=3 or 4, preferably as part of a molecule with is a carboxylic acid or a functional derivative thereof. Suitable precursors of this kind are those having the formula C H (CH=CI-ICH (CH CO R, where p is from 0 to 10. The compounds may be the free acid (in which case R =H) or a derivative such as an alkali metal or alkaline earth metal salt, amide; or an ester, such as one derived from a mono-, dior tri-hydric alcohol, for example ethyl, amyl, octyl, decyl, dodecyl and hexadecyl alcohols; preferably the alcohol is an unbranched alcohol containing not more than 20 carbon atoms. A preferred precursor of this kind is arachidonic acid Examples of compounds in which n equals 3 are octadeca- 6,9,12-trienoic, nonadeca 7,10,13 trienoic and eicosa-8,- 11,14-trienoic acids. Of these, the C acid can be isolated by known methods from the seeds of the genus Oenothera, particularly the species 0. lamarckiana and 0. fruticosa; and the C and C acids can be derived from the C acid by chain-lengthening according to the well known Arndt-Eistert reaction. For flavouring it is preferred to employ all the above acids in the all-cis configuration.

The precursor may itself be incorporated into the foodstuff, or it may be treated to yield the actual flavouring compound which, after purification or other treatment Which may be required, can then be added to the foodstuff.

The term incorporated as used herein includes distribution of the flavouring compound or its precursor over the surface of the foodstuff, for instance, by dipping, sprinkling or spraying.

Examples of methods which may be employed in the preparation of the active flavouring compound from the precursor are set out later in the specification, but a preferred way of obtaining the active compound from a precursor involves oxidation of the precursor in the presence of a suitable catalyst and molecular oxygen. A particularly valuable catalyst for this purpose is chlorophyll, by use of which the time required for oxidation of a precursor is commonly reduced by a factor of ten or more compared with the time required for oxidation in the absence of such a catalyst.

A particularly preferred method of obtaining the flavouring compound from the precursor involves autoxidation or oxidation of a percursor, followed by treatment with the bisulphite of an alkali metal, for example, sodium bisulphite. Generally the oxidised precursor is shaken with a solution of the bisulphite, after which the flavouring compound is separated by distillation or solvent extraction. Conveniently, the precursor is submitted to oxidation in the presence of chlorophyll, after which a solution of sodium bisulphite is added to the oxidation product and the mixture distilled, preferably by steam distillation. A1- ternatively, instead of adding a solution of the bisulphite of an alkali metal, a suitable amount of gaseous sulphur dioxide may be passed through the solution of the precursor either simultaneously with or subsequent to its oxidation.

Instead of preparing the flavouring compound by a process of chain shortening, such as normally occurs in the case of hydrolysis or oxidation of the precursor as described earlier, the flavouring compound may be synthesised from a simpler substance. We have found that a particularly successful synthetic sequence is one in which is formed, as an intermediate compound, 2,5-hexadiynal,

3 or an acetal or hemiacetal thereof. Details of the preparation and use of the diethylacetal of 2,5-hexadiynal in the preparation of aldehydes of the invention are set out later in the specification.

2,5-hexadiyna'l is a novel compound, as are its acetals and hemiacetals, and its use is not limited to the preparation only of the aldehydes mentioned; indeed, by selection of suitable reactants and reaction conditions these compounds may be employed in the synthesis of a wide range of long chain unsaturated carbonyl compounds in addition to those specified above.

As already indicated, the aldehydes are new compounds; as also are many of their precursors, particularly those capable of forming the aldehydes by oxidation or hydrolysis. The invention accordingly includes the aldehydes and those precursors that are new compounds, methods of preparing these compounds as described later and the new compounds synthesised en route. The invention also includes the use of the aldehydes and their precursors generally in flavouring food products, and the food products thus flavoured.

The amount of the aldehyde used in flavouring a foodstuff is generally about 1 part in -40 parts of food product and preferably 1 part in 10 to 10 parts, but proportions outside this range can be employed in some circumstances. When a precursor is added to the foodstuff it is preferably used in an amount sufficient to provide a quantity of the aldehyde with the range specified.

Since only a very small proportion of the flavouring compound or precursor is usually required it is often convenient to use it in conjunction with a suitable diluent, for example an inert solvent, such as a bland fat or oil, certain hydrocarbons, water and esters of higher fatty acids such as are used as solvents in the pharmaceutical industry.

The flavouring compound or precursor may also be used in conjunction with normally used fiavouring substances, so that the invention includes also flavouring compositions comprising the fiavouring compound of the invention, or a precursor thereof, and another flavouring substance.

When a precursor is employed, an improved savoury flavour may not develop immediately on the incorporation of the compound in the foodstuff; it will, however, usually develop within a few minutes of heating the product, or within a few hours of the product being allowed to stand in air at room temperature.

The invention is particularly applicable to the preparation of foodstuffs having an improved flavour of chicken. It can, for example, be employed to improve the natural flavour of chicken meat.

The invention is illustrated by the following examples.

EXAMPLE 1 (Preparation of undeca-trans-Z, cis-S-dienal) Hept-l-yne (B.P. 102 C., n 1.4082) prepared in 50% yield from sodium acetylide and amyl bromide, was treated, in the form of its Grignard derivative, with propargyl bromide in the presence of cuprous chloride as catalyst. The product, deca-1,4-diyne, B.P. 66-70 mm.; 11 1.4551, was obtained in yield.

Deca-1,4-diyne, as its Grignard derivative, reacted with orthoformic ester, to give 1,1-diethoxyundeca-2,5-diyne, B.P. 99.5100/0.2 mm.; n 1.4586 in 36% yield.

1,1-diethoxyundeca-2,5-diyne was hydrogenated over Lindlars catalyst (lead-poisoned palladium), and the product, containing 1,1-diethoxyundeca-2,S-diene, was hydrolysed with tartaric acid at 100.

The product contained 55% undeca-trans-Z, cis-S-dienal. [Dinitrophenylhydrazonez M.P. 113114; light absorption in chloroform, maximum 3780 A.]

4 EXAMPLE 2 (Preparation of 1,1-diethoxyhexa-2,5-diyne) Bromination of acrolein in CS at -30 gave, in 57% yield, 2,3-dibromopropanal, which was converted by orthoformic ester to 1,1-diethoxy-2,3-dibromopropane,

in yield. From this, 1,1-diethoxyprop-2-yne (propargyl aldehyde diethyl acetal) was prepared by dehydrobromination with sodamide in liquid ammonia in about 70% yield, B.P. 40-43/11 mm.; 12 1.4118.

1,1-diethoxyprop-2-yne, as its Grignard derivative, reacted with propargyl bromide in tetrahydrofuran with cuprous chloride as catalyst, to give 1,1-diethoxyhexa-2,5- diyne in 65% yield. This was a colourless liquid, B.P. 5757.5 0.05 mm.; n 1.4524, which crystallised completely at 15, and melted at ca. -2 to +1 C.

Found: 72.40% C; 8.56% H; 53.86% OC H 0 11 0 requires: 72.27% C; 8.49% H; 54.23% OC H EXAMPLE 3 (Preparation of tetradeca-trans-2, cis-5, cis-S-trienal) 1,l-diethoxyhexa-2,5-diyne (obtained as described in Example 2) as its Grignard derivative, reacted with Oct-2- yne bromide in tetrahydrofuran, with cuprous chloride as catalyst, to give 1,1-diethoxytetradeca-2,5,S-triyne in 37% yield. This was a pale yellow liquid, B.P. 160-165 /0.05 mm.; 11 1.4775, and was gas chromatographically pure.

Found: 78.27% C; 9.54% H; 32.46% OC H C H O requires: 78.80% C; 9.55% H; 32.84% OC H 1,1-diethoxytetradeca-2,5,8-triyne was hydrogenated over Lindlars catalyst with absorption of 104% of the amount (3 mol.) of hydrogen theoretically required for formation of the corresponding triene.

The product, obtained in 91% yield, was a pale yellow liquid B.P. 108-109/0.03 mm.; n 1.4614.

Found: 76.61%, 76.59% C; 11.28%, 11.39% 30.99%, 29.93% OC H I number 264.4, 263.3.

0 1-1 0 requires: 77.10% C; 11.50% H; 32.15% OC H I number 271.5.

1,1-diethoxytetradeca2,5,8-triene was hydrolysed with boiling 1% oxalic acid solution to give a mobile yellow oil, B.P. 9l%/0.05 mm., containing the parent triene aldehyde.

Light absorption in petroleum ether: maximum 2230 A, e=12540.

The dinitrophenylhydrazone (orange-yellow needles) had an M.P. of 93.5-94".

Light absorption: maximum 3750 A., e=28470 (in clt'rllorpform); maximum 3540 A., e=29870 (in petroleum e er EXAMPLE 4 (Preparation of heptadeca-trans-2, cis-5, cis-8, cis- 1 l-tetraenal) 1,1-diethoxyhexa-2,5-diyne, prepared as described in Example 2, was treated with ethyl magnesium bromide to form the Grignard derivative. This then, reacted in the presence of cuprous chloride, with 1-bromo-undeca-2,5- diyne in tetrahydrofuran to form 1,1-diethoxyheptadeca- 2,5,8,11-tetrayne. Isolation of this compound was complicated by the fact that it was rather explosive; however it was isolated by careful distillation at ISO-200 C./ 0.05 mm. as a colourless oil. This was immediately hydrogenated over Lindlars catalyst until uptake of hydrogen ceased. The product after solvent removal and distillation at ISO- C./ 0.05 mm. was almost colourless and consisted mainly of 1,1-diethoxyheptadeca-2,5,8,1l-tetraene.

Found: I.R. spectrum: a broad band around 720 cm.- (cis double bond enhanced by (CH 1056 and 1121 cm.- (acetal group); 1660 (cis double bond). There were also absorptions at 1700 crn.- (oz-I3 corrjugated aldehyde) and 3010 and 970 cm.- (trans double bond), suggesting hydrolysis giving rise to some free aldehyde.

The l.l-diethoxyheptadeca-2,5,8,l'l-tetraene was hydrolysed with boiling 1% oxalic acid solution to give a product containing the parent tetraene aldehyde.

The DNPH of this aldehyde was obtained directly from the acetal and separated as orange crystals, M.P. 74- 78 C.

Found: 64.0% C; 7.4% H; 13.6% N.

C H O N requires: 64.8% C; 7.1% H; 13.1% N.

UV. spectrum: max 375 m., e=28030 in chloroform.

LR. spectrum: absorptions about 985, 1644 and 3010- 3040 indicate a trans (Oi-[3) double bond.

EXAMPLE 5 (Preparation of dodeca-cis-3, cis-6-dienal) Deca-1,4-diyne (prepared as described in Example 1) reacted, in the form of its Grignard derivative, with -1-bromo-3-methylbutene-2 in the presence of cuprous cyanide. The product was Z-methyltetradeca-S,8-diyne-2- ene, obtained in 42% yield.

The 2-methyltetradeca-5,8-diyne-2-ene was then treated with perbenzoic acid (obtained from benzoyl chloride and sodium peroxide) for 1 hour, the epoxy compound so formed decomposed and the diol obtained extracted with ether and dried over magnesium sulphate. Further purification of the diol was by chromatography on an alumina (deactivated with 8% water) column, with elution with 100% ether.

The diol so obtained was next hydrogenated over Lindlars catalyst, giving methyltetradeca-S,8-diene-2,3- diol (n 1.4788), and this was then treated with sodium iodate in HgO/T-H-F. solution.

The aldehyde was extracted with ether, dried over magnesium sulphate and the ether evaporated.

EXAMPLE 6 This example illustrates the preparation of a flavouring agent according to the invention employing arachidonic acid as precursor.

1 gm. of arachidonic acid was added to a solution of 3.5 gm. of sodium bisulphite in 10 ml. of water and the Cit mixture shaken for 1 6 hours at room temperature. The

organic material was then extracted with chloroform, the solution filtered through a Celite pad and the chloroform removed at reduced pressure on a rotary evaporator. Light petroleum (40-60 C.) was added to the residue and a white precipitate settled out. This was centrifuged off, dissolved in chloroform and re-precipitated from chloroform with light petroleum.

30 mg. of the white powdered product so obtained were treated with dilute sodium hydroxide solution and then acidified with dilute hydrochloric acid to give a total volume of 1 ml. This was then mixed with 425 cc. of standard chicken noodle soup base, to give very noticeable enhancement of the chicken flavour of the soup.

EXAMPLE 7 Example 6 was repeated using 'y-linolenic acid instead of arachidonic acid. The product obtained had a very similar flavour to that obtained from arachidonic acid.

EXAMPLE 8 To a very dilute solution of sulphuric acid (3 drops of 2 N acid in 70 ml. of water) was added 1 gm. of arachidonic acid. This mixture was heated to boiling, and oxygen was bubbled through it with the simultaneous dropwise addition of a 25% solution of sodium bisulphite in water. The rate of addition was adjusted to maintain the volume of the mixture constant. The distillate was collected and, after removal of most of the sulphur dioxide on a rotary evaporator, was added to chicken 6 soup in an amount forming 0.1 ml. per 500 ml. of soup. The chicken flavour of the soup was improved very noticeably.

EXAMPLE 9 The process described in Example 8 was repeated, except that instead of adding a solution of sodium bisulphite to the reaction mixture a stream of sulphur dioxide was blown through it, together with the stream of oxygen. Again, the distillate obtained imparted a very good chicken flavour to a soup base.

EXAMPLE 10 A mixture of steam, sulphur dioxide and oxygen was passed through a sloping glass tube arranged so that the gases entered at the higher end and, after leaving the tube, passed immediately into a condenser. The tube was heated and ethyl arachidonate was allowed to fall, drop by drop, into it. The products of the reaction between the sulphur dioxide, oxygen and the ester were carried through the tube and condensed to give a condensate with a noticeable savoury (chicken-like) flavour.

EXAMPLE 11 This example illustrates that oxidation of arachidonic acid is an essential step in the formation from it of the flavouring agent of the invention.

The process of Example 8 was repeated, except that the water used was carefully boiled to remove dissolved oxygen, and instead of oxygen a stream of nitrogen was bubbled through the reaction mixture. The distillate collected had only a very slight taste of chicken, which was probably produced by antoxidation of the arachidonic acid prior to the rteatment described above.

EXAMPLE 12 The process described in Example 8 was repeated but using the ethyl ester of 'y-linoleic acid instead of arachigonic acid. The distillate obtained had a strong chicken avour.

EXAMPLE 13 The process described in Example 8 was repeated, using the ethyl ester of nonadeca-7,10,l3-trienoic acid instead of arachidonic acid. Again, a distillate having a strong chicken flavour was obtained.

EXAMPLE 14 This example illustrates the accelerated oxidation of methyl 'y-linolenate in the presence of chlorophyll.

The apparatus used consisted of a glass tube 30 cm. long and 2.5 cm. in diameter, one end of the glass tube being constricted to take rubber tubing. Inside the glass tube, immediately adjacent the constriction and sealed to the sides of the glass tube, was arranged a transverse sintered glass disc. The whole length of the glass tube was jacketed so that water could be passed around it to maintain the inside of the glass tube at a desired temperature.

In use, the tube was arranged vertically with the sintered disc and constricted region at the bottom.

15 gm. of methyl 'y-linolenate were placed in the tube above the sintered disc and a stream of oxygen was passed slowly thronugh the rubber tube, through the sintered disc and up through the ester. The pressure of the oxygen was suificient to prevent loss of ester downwards through the disc. A burette was arranged above the glass tube so that a 0.3% solution of chlorophyll in hexane could be added to the ester as required. Water at 20 C. was circulated around the glass tube.

The tube was irradiated by two 250 watt infrared lamps and the chlorophyll/hexane solution added to the ester at the rate of 0.01 ml. every 5 minutes. Reaction was allowed to continue for three hours, after which the tube was emptied and its contents taken up in carbon tetrachloride. The carbon tetrachloride solution was then shaken for 24 hours with a solution of ferrous ammonium sulphate, separated, and any organic material remaining in the ferrous ammonium sulphate extracted in fresh carbon tetrachloride. High vacuum distillation of the combined carbon tetrachloride solutions gave a fraction (B.P. 90-110" C./3 l0 mm.) having a very strong, clean chicken flavour.

EXAMPLE Ethyl arachidonate (83% pure) in hexane solution was passed through a chromatographic column packed with deactivated alumina to remove most of the added antioxidant (propyl gallate) and the ester was then treated as described in the previous example.

After extraction and distillation one fraction was obtained having a very strong chicken flavour.

EXAMPLE 16 1 ml. of ethyl arachidonate, which had been oxidised as described in Example 14 to the point where the ester was removed from the tube after irradiation, was steam distilled with 75 ml. of a 50% aqueous solution of sodium bisulphite, and the distillate collected.

The distillate had a good chicken flavour.

EXAMPLE 17 The process of Example 16 was repeated, except that 2 ml. of 2 N sulphuric acid were added to the oxidised ester before distillation was commenced. The distillate obtained had a very good chicken flavour.

EXAMPLE 18 The processes described in Examples 16 and 17 were repeated, using oxidised arachidonic acid instead of ethyl arachidonate. The distillate in each case had substantially the same flavour as when the ester was treated.

EXAMPLE l9 1 gm. of 'y-linolenic acid, oxidised as described in Example 14, was heated in a flask with 75 ml. of distilled water. During the heating a continuous stream of sulphur dioxide was bubbled through the mixture in the flask. The distillate was collected and was found to have a strong chicken flavour very similar to that obtained by the processes described in Examples 14 to 18.

EXAMPLE 20 This example illustrates how, according to the invention, a soup having only a weak flavour of chicken, resulting from the presence in it of chicken meat and chicken fat, can be given a more marked chicken flavour by the incorporation of arachidonic acid.

A conventional dry soup mixture was prepared by mixing together the following ingredients:

The mixture was then simmered in 800 cc. of water for 7 minutes, and soup having a weak flavour of chicken resulted.

A second dry soup mixture was then prepared, identical with the first except that the chicken fat employed was first mixed with 0.18 cc. of ethanol containing 10% by weight of commercially available (about 90% pure) arachidonic acid. The mixture was then simmered in 800 cc. of water for 7 minutes, to give a soup of excellent chicken flavour. It contained about 1 part of arachidonic acid per 50,000 parts of soup.

8 EXAMPLE 21 The diethyl acetal of tetradeca-2,5,8-trienal, obtained as described in Example 3, was added to a 1% solution of oxalic acid in water, and steam distilled under nitrogen so as to liberate the free aldehyde. The steam distillate so obtained was extracted with pentane and this solvent removed by evaporation under vacuum. The residue, comprising the aldehyde, was incorporated into a neutral soup base, at a concentration of 1 part in 10 giving a soup having a good chicken flavour.

EXAMPLE 22 Tetradeca-2,5,8-trienal obtained as described in Example 3 was diluted tenfold with ethanol and then 0.025 ml. of this diluted solution added to 850 cc. of neutral soup base. A very distinct mushroom flavour was apparent in the soup.

EXAMPLE 23 (Preparation of tetradeca-trans-Z, cis-4, cis-S-trienal) 22.2 g. undeca-LSdiyne and 2.0 g. cuprous chloride, in 200 ml. aqueous methylamine were stirred vigorously while 78.0 g. of 1,1 diethoxy-3-bromo-prop-2-yne was added dropwise in thirty minutes. The colour of the solution was maintained by the addition of small amounts of hydroxylamine hydrochloride as required. The mixture was cooled and extracted with ether and the ether extract washed with ammonium chloride solution and then water. The ether extract was then dried over magnesium sulphate and freed of solvent in vacuo.

The residue was distilled, giving a very pale yellow product (1,1diethoxy tetradeca-2,4,8-triyne): B.P. 124- 126/0.5 mm.; n :1.459; yield 36.0 g.; GLC purity ca. 95%.

U.V. spectrum: 203 ma (6 1082), 217 m (45 678), 226 ma (5 761), 234 m infl. (e 614), 255 mp. (e 232) in etha- 1101.

The triyne so obtained was hydrogenated to the triene over Lindlars catalyst.

Found: B.P. /4 mm.; 11 1.425.

EXAMPLE 24 Example 20 was repeated, except that instead of arachidonic acid, aldehydes prepared as described in Examples 1, 3, 4, 5 and 23 were incorporated into the soup.

EXAMPLE 25 (Preparation of tetradeca-trans-Z, trans-4, cis-8-trienal) The DNPH of the product obtained in Example 23 was converted to the trans-2, trans-4, cis-8 compound by acidification with 2 N hydrochloric acid.

What is claimed is:

1. A method of flavouring a foodstuff which comprises the step of incorporating in the foodstuff an aliphatic aldehyde or a precursor thereof, said aldehyde having the general formula RCHO Where R contains from 10 to 16 carbon atoms and from 2 to 4 double bonds with at least one of the double bonds being non-conjugated to a level such that the foodstuff contains one part of the aldehyde in about 10 to about 10 parts of the foodstuff.

2. A method according to claim 1, wherein the aldehyde is selected from the group consisting of undeca-2,5- dienal, dodeca-3,6-dienal, trideca-4,7-dienal, trideca-2,4,7- trienal, tetradeca-2,5,8-trienal, tetradeca-2,4,8-trienal, pentadeca-3,6,9-trienal, hexadeca-4,7,10-trienal, hexadeca-2,4, 7,10-tetraenal, and heptadeca-2,5,8,1l-tetraenal.

3. A method according to claim 1, wherein the aldehyde is tetradeca-2,5,8-trienal.

4. A method according to claim 1 which comprises the steps of:

(i) incorporating in the foodstuff an ester selected from the group consisting of an acetate of the formula 9 RCH(CH COO) and a propionate of the formula RCH(C H COO) corresponding to said aldehyde of formula RCHO, and

(ii) causing said ester to decompose in the foodstuff by hydrolysis to yield said aldehyde.

5. A method according to claim 1 which comprises the steps of:

(i) incorporating in the foodstuff a derivative of said aldehyde, said derivative being selected from the class consisting of an acetal, a hemiacetal and a bisulfite addition compound, and

(ii) causing said derivative to decompose by hydrolysis in the foodstuff to yield said aldehyde.

6. A method according to claim 5 in which said derivative is a dimethylacetal or a diethylacetal.

7. A method according to claim 1 which comprises the steps of:

(i) adding to the foodstulf an alcohol of the formula RCH OH corresponding to said aldehyde of formula RCHO, and

(ii) causing said alcohol to decompose by oxidation to yield said aldehyde.

8. A foodstuff having incorporated in it an aliphatic aldehyde of the general formula RCHO where R contains from to 16 carbon atoms and from 2 to 4 double bonds with at least one of the double bonds being non-conjugated, the amount of said aldehyde in the foodstuff being one part in about 10 to about 10 parts of the foodstuff to impart an enhanced flavour to the foodstuff.

9. A fiavouring composition for use with foodstuffs which comprises an ester selected from the group consisting of an acetate of the formula RCH(CH COO) and a propionate of the formula RCH(C H COO) corresponding to an unsubstituted, straight-chained aliphatic aldehyde having the formula RCHO, where R is a residue having from 10 to 16 carbon atoms and 2 to 4 double bonds with at least one of the double bonds being non-conjugated, said ester being hydrolysable to said aldehyde.

10. A fiavouring composition for use with foodstuffs, which composition comprises a derivative selected from the group consisting of an acetal, a hemi-acetal and a bisulfite addition compound of an unsubstituted, straight chained aliphatic aldehyde having the formula RCHO, where R is a residue having 10 to 16 carbon atoms and 2 to 4 double bonds with at least one of the double bonds being non-conjugated, said derivative being hydrolysable to said aldehyde.

11. A fiavouring composition according to claim 10 in which said derivative is a dimethylacetal or a diethylacetal.

12. A fiavouring composition for use with foodstuffs, which composition comprises an alcohol of the general formula RCHOH, said alcohol being oxidisable to an unsubstituted, straight-chained aliphatic aldehyde of the formula RCHO, where R is a residue having 10 to 16 carbon atoms and 2 to 4 double bonds, at least one of the double bonds being non-conjugated.

13. A fiavouring composition for use with foodstuifs, which composition comprises an aliphatic aldehyde of the general formula RCHO, where R contains from 10 to 16 carbon atoms and from 2 to 4 double bonds, at least one of the double bonds being non-conjugated.

References Cited UNITED STATES PATENTS 6/1963 Evans 99-440 OTHER REFERENCES MORRIS O. WOLK, Primary Examiner W. BOVEE, Assistant Examiner 

